"I'm coming now now." It is a joke because it is true. You meant it. You were, in your own mind, nearly ready. And then an hour had gone.

This is one of the most frustrating parts of living with an attention difference, partly because it is so easy for other people to read as disrespect. If you are late, you must not value my time. If you said five minutes and took two hours, you must have been lying.

What the research actually found

There is a real body of evidence here, and it is worth being precise about what it says, because the internet is not.

A meta-analysis of 27 studies, comparing 1,620 children and adolescents with ADHD against 1,249 without, found that the ADHD group judged time less accurately and less precisely, and had a greater tendency to overestimate how long something lasted.

A larger meta-analysis of 55 studies, covering children and adults, found a broad range of differences in timing: more difficulty telling apart very brief durations, more variability in estimating durations lasting several seconds, and patterns in time estimation and production that the authors described as consistent with an accelerated internal clock. They also found two separate things going on in time reproduction tasks: at short intervals, distraction slowed people down; at long intervals, a dislike of waiting sped them up.

Anyone who tells you science has proven "time blindness" explains your whole Saturday is overselling it. Anyone who tells you it is purely a discipline problem is ignoring a large and consistent literature. The truth sits in between, and it is still useful.

Why five minutes becomes five hours

Alongside the perception research, three ordinary mechanisms do a lot of the work:

  • Time stops being sampled. When attention locks onto something engaging, the habit of checking the clock disappears. Nothing interrupts, so nothing updates.
  • Estimates are built from the best case. You remember the one time the task took twenty minutes, not the four times it took ninety.
  • Transitions are not counted. "Fifteen minutes to get ready" is the shower. It is not the finding of the shirt, the charging of the phone, the looking for keys, the answering of one message.

What actually helps

The principle is the same as for forgetting: stop asking your head to do the job, and put the job in the world.

Make time visible

An analogue clock or a visible countdown in the room you are in does something a phone cannot: it shows time as a shrinking amount of space, continuously, without being opened. A phone has to be checked. A wall clock just is.

Time the thing once, honestly

Pick the task you most regularly misjudge. Next time, start a timer when you begin — including the preparation — and look at the number at the end. Do it three times and you will have a real figure. Most people find it is around twice their estimate, and from then on they can simply double.

Use arrival time, not departure time

"Leave at 6" fails because leaving is a process. "Be in the car at 6" is a single checkable fact. Then set the alarm for the thing before the thing: an alarm for "start getting ready", not for "go".

Put the alarm on the cue, not the clock

If-then plans — a specific trigger tied to a specific action — have good experimental support for helping people actually act on goals. "When the 5:30 alarm rings, I stand up and put my shoes on" beats "I'll start getting ready around half five."

Make the invisible middle visible

For anything with a deadline, write down the three things that have to happen before it, each with its own time. The deadline is not the task. The three things are the task.

On being late to other people

Two practical things, neither of which requires anyone to be diagnosed with anything.

Tell people the system, not the excuse. "I'm setting an alarm for 5:30 so I'm in the car at 6" is a sentence that builds trust. "Sorry, time ran away" is a sentence that spends it.

Pick the relationships where lateness actually costs something and over-engineer those. You do not need a perfect system for everything. You need a reliable one for the three things that matter.